Hi All. I have read through the "So what's the best brand/model tires for the C10?" sticky and decided to try the PR3/777 combo for my new-to-me 2004 C10. I didn't see it mentioned anywhere but the only Shinko 777 in the 150/80-16 size that I can find is listed as "Heavy Duty" on their web site. It is part # 87-4597. Is this the correct tire?